• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.166-170
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• 1993

Hirudin is a potent inhibitor of thrombin, which was originally obtained from the medicinal leech (Hirudo medicinalis) Now it is being produced through the recombinant technology on a large scale. Recombinant hirudin has been assayed for the anticoagulant activity by the measurement of clotting time and the inhibition of thrombin actvity using a chromogenic substrate. The assay range of partial thromboplastin time and thrombin time is within $0.2{\sim}1.0 {\mu}g/mι.$ Thrombin time is more sensitive to the measurement of clot. Ex vivo study showed the level of hirudin in rat plasma was highest in 10 min and then it was eliminated slowly. The half-life of r-hirudin was 80~110 min depending on the assay methods. Intraveneous injection of russel viper venom was used for thrombus induction combined with vents cava ligation. Inhibition of venous thrombosis was observed with i.v. hirudin. It was dependent on the concentration of hirudin.

• BMB Reports
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• v.47 no.7
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• pp.376-381
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• 2014

Enzymatic oxidation of pyrogallol was efficiently transformed to an oxidative product, purpurogallin (PPG). Here, the anticoagulant activities of PPG were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). And, the effects of PPG on expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were evaluated in tumor necrosis factor (TNF)-${\alpha}$ activated human umbilical vein endothelial cells (HUVECs). Treatment with PPG resulted in prolonged aPTT and PT and inhibition of the activities of thrombin and FXa, as well as inhibited production of thrombin and FXa in HUVECs. In addition, PPG inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. PPG also elicited anticoagulant effects in mice. In addition, treatment with PPG resulted in significant reduction of the PAI-1 to t-PA ratio. Collectively, PPG possesses antithrombotic activities and offers a basis for development of a novel anticoagulant.

• Journal of Life Science
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• v.14 no.3
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• pp.509-513
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• 2004

Inhibitory activities of 58 methanol extracts, which were prepared from different parts of 55 kinds of edible and medicinal plants, against human thrombin were evaluated. Analysis of the anti-coagulation activity determined by thrombin time enabled us to select 8 herb extracts as possible sources of anti-thrombosis agent. Further analysis of anti-thrombosis activity determined by activated partial thromboplastin time and fibrinolytic activity, and heat stability and inhibition against other proteolytic digestive enzymes provided new information that Pimpinella brachycarpa, Lysimachia clethroides, and Salix gracilistyla could be used as a potential anti-thrombosis agent. Our results suggest that edible and medicinal plants could be the potential source of thrombin inhibitor.

• Korean Journal of Pharmacognosy
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• v.35 no.1 s.136
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• pp.52-61
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• 2004

Inhibitory activities of 264 methanol extracts, which were prepared from different parts of 210 kinds of wild and medicinal plants, against human thrombin were evaluated. Based on the anti-coagulation activity determined by thrombin time and activated partial thromboplastin time, the 14 extracts were screened. The fibrinolytic activity, heat stability and inhibition of other proteolytic digestive enzymes, such as pepsin, papain, trypsin and chymotrypsin, of the 14 extracts were further determined, and Ginko biloba (herba), Ephedra sinica (radix), Reynoutria elliptica (herba), Amomum tsao-ko Crevost (fructus), and Magnolia officinalis Rehd. et Wils (bark) were finally selected as possible plant sources for anti-thrombosis agent. These results suggested that medicinal and wild plants could be the potential source of thrombin inhibitor.

• Journal of Mushroom
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• v.13 no.1
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• pp.30-36
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• 2015

Our study investigated the fibrinolytic, thrombin inhibitory, anti-oxidative and anti-inflammatory activities of the water extract and solvent fractions isolated from Pleurotus ferulea. Fibrinolytic activity was investigated using the fibrin plate method. Thrombin inhibitory activity was used to analyze thrombin inhibitor assay. The DPPH assay was used to estimate anti-oxidative activity. Inhibition of NO production was measured for anti-inflammatory activity in LPS-activated murine RAW 264.7 macrophage cells. An MTS assay was used to evaluate the effects of the water extract and solvent fractions isolated from Pleurotus ferulea on cell viability. Our results showed the fibrinolytic activity to be strong in the ethyl acetate fraction at 1.33 plasmin units. The ethyl acetate fraction also showed high thrombin inhibitory activity at 94.45%. The anti-oxidative activity of the water extract was 37.01% and the anti-inflammatory activity of the chloroform fraction was 98.13%. These findings suggest that Pleurotus ferulea's extract and fractions could be applicable in the development of functional foods for the treatment and prevention of cardiovascular diseases.

• BMB Reports
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• v.46 no.10
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• pp.484-489
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• 2013

Piperlonguminine (PL), an important component of Piper longum fruits, is known to exhibit anti-hyperlipidemic, antiplatelet and anti-melanogenic activities. Here, the anticoagulant activities of PL were examined by monitoring activated-partial-thromboplastin-time (aPTT), prothrombin-time (PT), and the activities of thrombin and activated factor X (FXa). The effects of PL on the expressions of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) were also tested in tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) activated HUVECs. The results showed that PL prolonged aPTT and PT significantly and inhibited the activities of thrombin and FXa. PL inhibited the generation of thrombin and FXa in HUVECs. In accordance with these anticoagulant activities, PL prolonged in vivo bleeding time and inhibited TNF-${\alpha}$ induced PAI-1 production. Furthermore, PAI-1/t-PA ratio was significantly decreased by PL. Collectively, our results suggest that PL possesses antithrombotic activities and that the current study could provide bases for the development of new anticoagulant agents.

• BMB Reports
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• v.48 no.10
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• pp.577-582
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• 2015

Cyclopia subternata is a medicinal plant commonly used in traditional medicine to relieve pain. Here, the anticoagulant effects of scolymoside, an active compound in C. subternata, were examined by monitoring activated partial thromboplastin time (aPTT), prothrombin time (PT), and the activities of thrombin and activated factor X (FXa). The effects of scolymoside on plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) expression were evaluated in tumor necrosis factor (TNF)-α-activated human endothelial cells. Treatment with scolymoside resulted in prolonged aPTT and PT and the inhibition of thrombin and FXa activities and production. In addition, scolymoside inhibited thrombin-catalyzed fibrin polymerization and platelet aggregation. Scolymoside also elicited anticoagulant effects in mice, including a significant reduction in the PAI-1 to t-PA ratio. Collectively, these findings indicate that scolymoside possesses anticoagulant activities and could be developed as a novel anticoagulant.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.266-273
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• 1991

Hirudin, a 65-amino acid protein isolated from the salivary gland of the bloodsucking leech, Hirudo medicinalis, is a potent thrombin-specific inhibitor and blocks the thrombin-mediated conversion of fibrinogen to fibrin in clot formation. We have studied the gene expression and secretion of hirudin in yeast. Saccharomyces cerevisiae. A gene coding for hirudin was synthesized based on the amino acid sequence and cloned into a yeast expression vector $YEG{\alpha}-1$ containing the ${\alpha}-mating$ factor pre-pro leader sequence and galactose-inducible promoter, GALl0. Recombinant S. cerevisiae was found to secrete biologically active hirudin into the extracellular medium. The secreted recombinant hirudin was recovered from the culture medium and purified with ultrafiltration and reverse phase high performance liquid chromatography. Approximately 1 mg of hirudin per liter was produced under suboptimal culture conditions and brought to about 90% purity in two steps of purification.

• Archives of Pharmacal Research
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• v.26 no.3
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• pp.224-231
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• 2003

The anti-thrombotic effects of LB30057, a direct thrombin inhibitor, were evaluated with in vivo rat and dog thrombosis models. In rats, 1 mg/kg of LB30057 inhibited half of the clot formations in the inferior vena cava at 5 minutes after intravenous application. When measured at 2 hours after oral application, 100 mg/kg prevented approximately half of the clot formations in the inferior vena cava and 50 mg/kg prolonged the mean occlusion time from $15.6{\pm}1.3$ minutes to $47.2{\pm}8.3$ minutes in the carotid artery. In dogs, the formation of thrombus in the jugular vein was reduced to half at a dose range of 20-30 mg/kg at 6 hours after oral application. In addition, the LB30057 dosage required to reduce venous clot formation by approximately 80-90% in dogs was only about 10% of that required for the same reduction in rats. This is probably due to the variation in its time-dependent blood concentration profiles in each species; for example, the plasma half-life of LB71350 in dogs was longer than that in rats ($153.0{\pm}3.0$ vs. $129.7{\pm}12.7$ min at 30 mg/kg, i.v., respectively). AUG, $T_{max},{\;}G_{max}$, and BA in dogs were 59, 8.9, 9.17, and 13.3 times higher than those in rats at oral 30 mg/kg, respectively. Taken together, these results suggest that LB30057 administered orally is effective in the prevention of arterial and venous thrombosis in rats and dogs. It therefore represents a good lead compound for investigations to discover a new, orally available, therapeutic agent for treating thrombotic diseases.

• Journal of Life Science
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• v.18 no.3
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• pp.363-368
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• 2008

The in vitro thrombin inhibitory activities of 304 crude extracts from 76 kinds of korean wild insects were evaluated. Measurement of thrombin time showed that the DMSO extracts of Acrida cinerea cinerea (Thunberg), Anax parthenope julius Brauer, Eurydema rugosa Motschulsky, and Stethophyma magister (Rehn) and the water extracts of Dolycoris baccarum Linne, Lixus divaricatus Motschulsky, Metrioptera bonneti, Moechotypa diphysis (Pascoe), Nicrophorus concolor sp., and Tomapoderus ruficollis (Fabricius) had strong thrombin inhibitory activity. No prominent changes of activated partial thromboplastin time by treatment of the selected extracts suggested direct inhibition of thrombin activity by the insect extracts. DPPH scavenging activity of selected extracts showed that the extract of A. cinerea cinerea (Thunberg), D. baccarum Linne, L. divaricatus Motschulsky and N. concolor sp. has good antioxidant activity as well as antithombin activity. Our results suggested that some of korean wild insects could be developed as a natural source of antithrombosis.